An image sensor is a semiconductor device for converting an optical image into an electrical signal. An image sensor may be classified as a charge coupled device (CCD) image sensor or a complementary metal oxide silicon (CMOS) image sensor.
The CMOS image sensor may include a photodiode and a MOS transistor within a unit pixel for sequentially detecting electrical signals of each unit pixel, thereby implementing an image.
Manufacturing processes of a CMOS image sensor may include forming a microlens by patterning and then reflowing an organic photoresist on and/or over a semiconductor substrate including a unit pixel and relevant devices. However, the organic photoresist may have weak physical properties and thus, the microlens may be easily damaged by physical impact that may result in cracks, etc. in subsequent processes such as a package and bump, etc. The relative viscosity of the organic photoresist is strong so that a defect of the microlens may develop when a particle is absorbed.